Phase Change Material (PCM) is suitable for storing thermal energy in the form of latent heat. This latent heat can be utilized for heating and cooling application without changing its form. A Phase Change Material (PCM) is a substance with a high heat of fusion which melts and solidifies at a certain temperature and is also capable of storing and releasing of energy. The Phase Change Material (PCM) changes from solid to liquid and vice versa when heat is absorbed or released by it.
U.S. Pat. No. 6,217,993 discloses the use of fibers having microencapsulated Phase Change Material (PCM) and fabrics made from them. Microcapsules are expensive, can rupture, need additional resinous agents for adhesion and can cause poor fabric flexibility and properties.
U.S. Pat. No. 6,793,856 discloses fibers made with polymeric material which are dipped in Phase Change Material (PCM) to produce Form Stable Phase Change Material (FSPCM).
U.S. Pat. No. 5,989,335 issued to Soroushian discloses using mechanical action to reduce the bonding between fibers so that the fibers can be dispersed in matrix. One disadvantage of using mechanical means to break the inter-fiber bonding is that once the mechanically dispersed fibers are placed in the mixture, hydrogen bonds can again form between the fibers and cause the fibers to recluster in the mix.
U.S. Pat. No. 7,320,770 discloses the use of only polymer and mono hydroxy alcohol, fatty acids and paraffin waxes to produce Form Stable Phase Change Material (FSPCM).
Further, many patents focus on non-exuding property of Form Stable Phase Change Material (FSPCM). For example, U.S. Pat. No. 5,520,103 and U.S. patent application Ser. No. 12/736,258 discloses non-exuding property of Form Stable Phase Change Material (FSPCM). But these patents do not have any reference to brittleness and low tensile strength of Form Stable Phase Change Material (FSPCM) below the transition temperature.
Again U.S. patent application Ser. No. 11/0786 and U.S. patent application Ser. No. 12/174,607 describes a complicated process for preparing Phase Change Material (PCM) and polymer blend for thermal management.
The polymer matrix chosen earlier to support the Phase Change Material (PCM) is more than 20% which reduces the available latent heat of the Phase Change Material (PCM). U.S. patent application Ser. No. 11/258,779 and U.S. patent application Ser. No. 12/736,258 discloses that the use of more than 60% Phase Change Material (PCM) decreases the mechanical strength of the composite.
EP Patent Application No. 07007327.5 describes fiber reinforced cement composite materials using chemically treated fibers with improved dispersibility.
Therefore there exists a need for a Reinforced Form Stable Phase Change Material (RFSPCM) which is nontoxic, flexible and has high latent heat and high tensile or tearing strength, both above and below the melting point of Phase Change Material (PCM). The stable composition of the present invention can easily be heated and cooled without changing the structure and composition and also without exuding its Phase Change Material (PCM). The present invention provides a Phase Change Material (PCM) product for providing stored heat that has improved safety and handle ability.
The novelty in the present invention is the reinforcement of polymer or Phase Change Material (PCM) matrix by mixing with chemically treated fiber, which gives the blend of a more stable form than so far obtainable and has high tensile or tear strength either above or below the melting point of the Phase Change Material (PCM).